Khan, who has two two teenage daughters, said he is worried about ads that can cause women to be “ashamed of their bodies,” saying, "it is high time it came to an end."

“Nobody should feel pressurised, while they travel on the Tube or bus, into unrealistic expectations surrounding their bodies and I want to send a clear message to the advertising industry about this,” he said in a statement.

The new advertising policy, which comes in response to customer feedback, will be upheld by an appointed steering group who will regularly review campaigns. Graeme Craig, TfL's commercial development director, explained how ads on public transportation differ than those on TV, online and in print.

"Our customers cannot simply switch off or turn a page if an advertisement offends or upsets them, and we have a duty to ensure the copy we carry reflects that unique environment. We want to encourage great advertising that engages people and enhances the transport network,” he said.